This invention relates to electromechanical printers of the type having a rotary print wheel mounted on a translatable carriage, commonly known as "daisy wheel printers".
Printing devices are known which employ a rotary print wheel mounted on a carriage for translation across the width of the print throat area for character printing. The carriage is typically mounted for sliding movement along a pair of spaced guide rods arranged in parallel fashion to the axis of a rotatable platen, and the print wheel is typically removably carried by the output shaft of a motor mounted to the carriage for translation therewith. A print hammer assembly is typically mounted above the print wheel motor, along with a support plate and driving mechanism for a removable ribbon cartridge. The removable ribbon cartridge typically contains either an endless ribbon or a ribbon mounted on a pair of reels. These mechanical mechanisms are typically contained within a printer housing, along with a carriage drive motor, motion translation mechanisms such as belts or cables and pulleys mechanically coupled between the carriage drive motor and the carriage, a platen stepper motor, a motion translating mechanism coupled between the platen stepper motor and the platen for providing paper feed around the platen, a paper deflector and pressure rollers, a mechanism for operating the platen pressure rollers, various switches and the electronic circuitry required to operate the mechanical components of the printer.
In the past, the carriage typically included a plurality of individual arm and platform members fastened together with individual fasteners and providing an upper carriage assembly and a lower carriage assembly pivotably mounted with respect to one another.
The removable ribbon cartridge is normally supported on a platform using some type of releasable latching mechanism, which enables a spent cartridge to be removed and replaced by a fresh cartridge. While several latching mechanisms are known, all suffer from one or more disadvantages, which include multi-element latches requiring the separate assembly of individual component parts, the use of separate guide posts or mechanical cartridge stops for registration purposes, and interally molded, frangible loction studs.